[RE-wrenches] Utility data monitoring....

[North Texas Renewable Energy Inc]

Wrenches
I was looking at the Global Spec newsletter in my inbox before I deleted it when a picture of a kW hr meter caught my eye. I followed the link to http://www.enetics.com/ to see what their PowerNode Recorders were all about. 
After an inquiry to Enetics support staff , a quick reply told me two things:
  1.. This PowerNode Recorder would do a dandy job of short or long term monitoring a utility source, hz, V and A, at the customers utility-grade meter (see below)
  2.. I cannot justify the price quite yet
Maybe if we all chipped in....

Jim Duncan
North Texas Renewable Energy Inc
817.917.0527
ntrei at earthlink.net
www.ntrei.com 

Hello Jim,
We recently installed a PowerNode for exactly that application.  The homeowner has 2 inverters, plus grid power of course.
The meter recorder has 4 voltage channels and 4 current channels; so we run Grid L1 to channel 1, Grid L2 to channel 2, Inverter 1 to channel 3, and Inverter 2 to channel 4.  The PV inverters are 240 volt, so we route one wire through the channel CT in the '+' direction and the other PV wire through the same CT in the opposite or '-' direction.  This gives us the TOTAL PV current (and therefore kW) for both legs of the PV.  All of these channels are recorded, stored, and registered separately.

Our reports are all in MS Excel format so the homeowner just gets his net meter values numerically in Excel.

If you wanted to see live net metered values in the meter, again, we just route the load wires through the Grid Cts so that the PV nets out against the Grid.  Everything is sychronous because the PVs are phase-locked to the grid.

Hope this helps.  Let me know if I can answer anything else.
Regards,
Bill Bush
585-924-5010
  -----Original Message-----
  From: North Texas Renewable Energy Inc [mailto:ntrei at earthlink.net] 
  Sent: Tuesday, January 27, 2009 4:04 PM
  To: support at enetics.com
  Subject: PowerNode Recorders


  After looking at the PowerNode Recorders on the Globalspec www site, I have a question.
  Say I install a grid interactive solar PV system on a customers home and the 120/240 AC output side of the inverter feeds through a customer owned form S2 meter then onto the utility service entrance thru the main breaker and back onto the grid. 
  Can the PowerNode Recorder distinguish between inverter generated power being backfed and utility power feeding inbound? Does the instrument record those different inflow and outflow on separate registers?
  Thanks
  Jim Duncan
  North Texas Renewable Energy Inc
  817.917.0527
  ntrei at earthlink.net
  www.ntrei.com 
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